New Zealand Journal of Crop and Horticultural Science abstracts

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Location of deterioration within garden pea (Pisum sativum) cotyledons is associated with the timing of exposure to high temperature

T. Shinohara

Department of Agronomy
Kasetsart University
Bangkok 10900, Thailand

J. G. Hampton

Bio-Protection and Ecology Division
P.O. Box 84, Lincoln University
Canterbury, New Zealand
email: hamptonj@lincoln.ac.nz

M. J. Hill

Seed Technology Institute Australia Pty Ltd
P.O. Box 410, Blackwood
SA 5051, Australia

Abstract Plants of two garden pea (Pisum sativum) cultivars (‘Alderman’ and ‘Early Onward’) were exposed to high temperature (30/25°C; day/night, 12 h each) at five different stages (during seed development, S1 - S2; at physiological maturity (PM), S3; and during seed maturation, S4 - S5) to determine the effect of high temperature on seed quality parameters and the location of deteriorated tissues within the cotyledons at each stage. High temperature applied at the beginning of seed filling (S1) significantly decreased thousand seed weight in both cultivars, and germination in ‘Alderman’. Hollow heart was significantly increased in both cultivars when high temperature was applied at the rapid seed fill stage (S2), but not when applied at other stages. There was a significant cultivar by treatment duration interaction at S2 for hollow heart incidence - ‘Alderman’ was more susceptible to hollow heart than ‘Early Onward’. Single seed conductivity was significantly increased by high temperature at S4 and S5 in both cultivars, and in ‘Alderman’ high temperature at S1 - S3 also increased leachate from the seeds. The location of deteriorated cells within the cotyledons differed depending on the timing of the high temperature treatment. Treatment at S2 resulted in deterioration at the adaxial surface of the cotyledons; with treatments at S4 - S5, deterioration occurred at the abaxial cotyledonary surface. The results suggest that the susceptible portion of pea cotyledons to high temperature during pre-PM stages is different from that during post-PM stages, and that the hollow heart test and the conductivity test detect deterioration located at different positions within the cotyledons. This may lead to the occasional inconsistency between the two tests.

Keywords Pisum sativum; garden pea; seed vigour; hollow heart; conductivity; temperature; seed development; seed maturation; cultivar

 

New Zealand Journal of Crop and Horticultural Science, 2006, Vol. 34: 299 - 309
0014 - 0671/06/3404 - 0299      © The Royal Society of New Zealand 2006
H06061; Online publication date 5 October 2006. Received 26 June 2006; accepted 25 August 2006

 

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